A sequence of submerged peat in the southern part of Lake Vättern in Sweden has been investigated. The rate of soil formation is calculated. An approximate date of thePiceaimmigration to this region of 800 A. D. is given. The submergance of the peat is due to the overturning of the lake, caused by the irregular land upheaval. The northern parts of Lake Vättem show considerably greater land upheaval figures than the southern parts, thus turning over the lakes water to the south. The overturning effect can, according to two different methods of calculation, be estimated to some 17 cm or 9 cm per century.